A conventional method and apparatus is described in German Application No. 41 23 783 (corresponding to U.S. Pat. No. 5,419,622). This German Patent Application describes a traction control system where at least one driving wheel has the tendency to spin, and this wheel is braked through the actuation of the associated wheel brake. The brake system disclosed in this document is a hydraulic brake system where pressure is built up and reduced in the wheel brakes through activation of a pressure-generating means (pump) and through actuation of a valve arrangement. To build up and reduce pressure within the framework of the traction control system, in accordance with a conventional method, a sequence of pressure-buildup pulses or pressure-reduction pulses including pulses of predetermined length is established based on the deviation of the wheel speed of the wheel tending to spin from a reference speed.
The above-described conventional method and apparatus do not consider that the dynamics of the pressure buildup or reduction is a function of different factors, such as temperature (outside temperature or temperature of the hydraulics), a change in the base pressure brought about by the pressure-generating means, and/or the level of the voltage supply of the pressure-generating means. Hence, there can be a deterioration of pressure-change dynamics in some cases.
It is therefore the object of the present invention to provide measures for improving the pressure-change dynamics.
In addition to the traction control system, pressure changes occur in at least one wheel brake within the framework of other control or regulating systems, such as an anti-lock brake system, a driving-dynamics regulating system or an electrical brake control. These problems can also occur in these areas of application, both in hydraulic and pneumatic brake systems.